6.6-stable review patch. If anyone has any objections, please let me know.
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From: Niklas Cassel cassel@kernel.org
commit 8e59a2a5459fd9840dbe2cbde85fe154b11e1727 upstream.
When ata_qc_complete() schedules a command for EH using ata_qc_schedule_eh(), blk_abort_request() will be called, which leads to req->q->mq_ops->timeout() / scsi_timeout() being called.
scsi_timeout(), if the LLDD has no abort handler (libata has no abort handler), will set host byte to DID_TIME_OUT, and then call scsi_eh_scmd_add() to add the command to EH.
Thus, when commands first enter libata's EH strategy_handler, all the commands that have been added to EH will have DID_TIME_OUT set.
Commit e5dd410acb34 ("ata: libata: Clear DID_TIME_OUT for ATA PT commands with sense data") clears this bogus DID_TIME_OUT flag for all commands that reached libata's EH strategy_handler.
libata has its own flag (AC_ERR_TIMEOUT), that it sets for commands that have not received a completion at the time of entering EH.
ata_eh_worth_retry() has no special handling for AC_ERR_TIMEOUT, so by default timed out commands will get flag ATA_QCFLAG_RETRY set, and will be retried after the port has been reset (ata_eh_link_autopsy() always triggers a port reset if any command has AC_ERR_TIMEOUT set).
For a command that has ATA_QCFLAG_RETRY set, while also having an error flag set (e.g. AC_ERR_TIMEOUT), ata_eh_finish() will not increment scmd->allowed, so the command will at most be retried scmd->allowed number of times (which by default is set to 3).
However, scsi_eh_flush_done_q() will only retry commands for which scsi_noretry_cmd() returns false.
For a command that has DID_TIME_OUT set, while also having either the FAILFAST flag set, or the command being a passthrough command, scsi_noretry_cmd() will return true. Thus, such a command will never be retried.
Thus, make sure that libata sets SCSI's DID_TIME_OUT flag for commands that actually timed out (libata's AC_ERR_TIMEOUT flag), such that timed out commands will once again not be retried if they are also a FAILFAST or passthrough command.
Cc: stable@vger.kernel.org Fixes: e5dd410acb34 ("ata: libata: Clear DID_TIME_OUT for ATA PT commands with sense data") Reported-by: Lai, Yi yi1.lai@linux.intel.com Closes: https://lore.kernel.org/linux-ide/ZxYz871I3Blsi30F@ly-workstation/ Reviewed-by: Damien Le Moal dlemoal@kernel.org Link: https://lore.kernel.org/r/20241023105540.1070012-2-cassel@kernel.org Signed-off-by: Niklas Cassel cassel@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/ata/libata-eh.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -636,6 +636,7 @@ void ata_scsi_cmd_error_handler(struct S /* the scmd has an associated qc */ if (!(qc->flags & ATA_QCFLAG_EH)) { /* which hasn't failed yet, timeout */ + set_host_byte(scmd, DID_TIME_OUT); qc->err_mask |= AC_ERR_TIMEOUT; qc->flags |= ATA_QCFLAG_EH; nr_timedout++;